Motor



Oct. 24, 1939.

IOTOR Filed Nov. 25, 1937 Patented Oct. 24, 1939 PATENT OFFICE Moron Harold Carlson, Tuckahoe, N. Y., assignor to The Associated Press, New York, N. Y., a corporation of New York Application November 23, 1937, Serial No. 176,001

2 Claims.

This invention relates to a motor and more particularly to a fractional horse-power motor adapt-- ed for synchronous operation with a relatively high frequency current, such as a carrier current.

An object of the invention is the provision of a motor suitable for driving phonographs for radio and moving picture broadcast and recording purposes, and also picture transmission apparatus and other like equipment which require synchro- 10 nous driving motors.

Other objects will appear in the following description given with the aid of the accompanying drawing, of which there is but one sheet.

Referring now to the drawing:

Figure 1 shows a side view of the motor together with a schematic drawing of a picture scanning system.

Figure 2 is a front elevation of the motor with the casing partly cut away.

Figure 3 shows a three-armed flange.

Figure 4 a side view of a three-armed flange.

Figure 5 is a vertical section taken through the motor shaft and rotor.

Referring to Figure 1 of the drawing:

Reference character I indicates a casting which with cap 34 forms the outer shell of the motor. The casting may be provided with suitable lugs or a base according to well known practice, by which the motor may be secured in position. Motor shaft 2 is connected to shaft 4 by means of a toothed clutch 3 shown diagrammatically in the drawing. Armature 5 controlled by magnet 6 serves to operate the clutch.

Shaft 4, in the present embodiment, drives a picture scanning drum 1. It will be understood that the apparatus shown, other than the motor, is represented schematically.

Worm 8 secured to shaft 4 mesheswith a worm gear 9 on shaft III which turns in bearings II and I2. Worm l3 on shaft l meshes with worm gear l4 on threaded shaft l parallel to the axis of drum I.

Shaft I5 is threaded intoa lead nut l6 secured to a lamp housing and optical system ll which projects a beam of light onto a strip'of sensitized material which may be secured to drum 1. The lamp housing slides on rod ll which prevents the housing from rotating with shaft Ii and causes the light beam to scan the drum when shaft i5 is driven by the motor through the train of mechanism just described. A suitable means, not

shown, is provided for disengaging the lead nut from leadscrew I! when the scanning light is returned to an initial position.-

In order to eliminate vibration caused by reduction gearing, it is desirable to have a direct drive between the motor and drum. In the present embodiment, the motor is designed to rotate at the rate of R. P. M. with a 2400 cycle current from a suitable oscillator l9, preferably of the fork driven type, synchronized with, or controlled by an incoming carrier frequency modulated by a picture being scanned by a distant picture transmitting apparatus.

In picture transmission systems now used by certain newspaper organizations, stations are scattered from coast to coast throughout the country, the various stations being provided with sending and receiving apparatus and the usual arrangement is, that while one station transmits a picture the receiving apparatus in the other stations is synchronized with the transmitter. Line time is very expensive, and it is essential that every possible second he profitably utilized. Consequently, it is desirable, that when a station transmits a series of pictures that the receiving motors remain constantly running after being initially synchronized with the transmitter.

In the past, it has been found that frequently one or more of the receiving motors of a system would be thrown out of synchronism when the load of the drum and scanning mechanism was suddenly applied to the motor shaft which necessitated re-transmitting the picture, with a resulting loss of line time. By means of the novel arrangement, now about to be described, such delay is eliminated, and receiving motors may be kept constantly running during a series of pictures.

Referring now to Figure 2 of the drawing which shows a motor having a fleld winding 20 disposed on permanently magnetized polepieces 2|, there being eight polepieces in the present embodiment, each of which has a series of teeth 22 which cooperate with teeth 25 formed in a laminated ring 28 secured by rivets 21 to a floating flywheel 28 supported on shaft 2.

One face of the flywheel part of the rotor is recessed at 29, and keyed to shaft 2 immediately adJacent to the depression in the flywheel is a three-armed flange or spider 30. In the present embodiment, the flywheel is provided with three studs ll, projecting outwardly beyond the edges of the arms of spider 30, the arms being normally held against the studs by springs 32 connected between the outer part of the spider arms and spring posts 33 in the face of the flywheel.

A floating washer is disposed on the shaft on each side of the assembly just described, and beyond the washers are ball bearing assemblies Ii which are pressed onto the shaft and fit in suitable recesses in the motor casing.

In operation, the motor is started by manual rotation. Magnet 8 and armature B are controlled from the sending station, and all receivers are started in synchronism with the transmitter. During normal rotation, either with or without a load, the arms of spider 30 rest against studs 3i as shown in the drawing. when a load is suddenly applied to shaft 2, such as caused by the engagement oi clutch 3, the impact causes shaft 2 and spider 30 to lag momentarily, but since the flywheel assembly is tree on the shaft, the rotor does not lose synchronism as it is yieldingly connected to the shaft through springs 32 and spider 30. The springs draw the spider and shaft back against studs II where the spider is held-until some subsequent operation of the clutch.

What is claimed is: 1. In a synchronous motor, a shaft, a spider keyed to said shalt, a rotor comprising a flywheel and a toothed ring adapted to turn in synchronism with an operating current, stop means carried by said rotor adapted to cooperate with the arms of said spider, and means adapted to maintain the arms of said spider in contact with said stop means during normal operation of said m0- tor, said means comprising springs connecting the arms of said spider with said rotor.

2. In a synchronous motor, a shalt, a spider keyed to said shaft, a rotor comprising a flywheel and a toothed ring adapted to turn in synchronism with an operating current, stop means carrled by said rotor adapted to cooperate with the arms of said spider, a driving connection between the arms of said spider and said rotor tending to prevent relative movement of these parts when the motor is operating under normal load conditions, said connection comprising spring means adapted to yield momentarily on the application 0! a sudden load to the shaft.

, HAROLD CARI-SON. 

